Tomato harvesters mechanically harvest by moving through a row of growing tomato plants, severing the plants below ground and picking up the severed plants along with their tomatoes, and also, picking up loose tomatoes and dirt. The loose dirt is returned to the ground in most cases quite readily, but the dirt clods accompany the vine and fruit up the elevator. Before reaching the shaker, the fruit passes over a gap between a lower segment of the elevator and an upper segment. Into this gap fall the dirt clods. The vines and fruit, except for some loose fruit which falls off with the dirt clods and which is afterwards recovered, continues with the upper segment of the elevator into the separator. There, walking bars are arranged in two sets 180.degree. out of phase and are moved by a crankshaft at the rear end of the harvester, being pivotally mounted at the front end of the shaker. The crankshaft provides a shaking action which separates the tomatoes from the vines. The tomatoes fall down onto a collecting conveyor below the shaker, while the vines are propelled out the rear of the machine. Above the walking bars are positioned a series of tines, so mounted as to retard the progress of the vines through the machine, and thereby submit them to somewhat more shaking than they would get if they were simply bounced along and cast out prematurely before all the tomatoes were recovered. For that reason these mounted tines are often referred to as vine retarders.
The invention addresses three main problems. The first has to do with the freeing of the vines and fruit from the clods at the gap referred to above. Depending on the weather conditions and the soil conditions, the sizes of the clods vary. Sometimes they are quite large and sometimes they are small. Heretofore, there has been no efficient system for rapidly adjusting the spacing at the gap through which the clods fall onto the cod conveyor. It may be possible in some machines to make such an adjustment by a major remounting of certain of the machine parts, but this takes time and is inconvenient. Certainly it has not been possible heretofore to make the change rapidly in the field or to make changes rapidly as the machine moves from one part of the field to another.
One general object of the present invention is to provide ready adjustment of the spacing apart of the two elevator segments above and below the the clod-receiving gap, enabling rapid adjustment at any time, even during the operation of the harvester.
A second problem relates to the vine retarders. According to growth conditions of the vines and some other factors, it has sometimes been found that the angles at which the tines are placed may be ideal under some harvesting conditions, and far from ideal under others. Here again, the vine retarders have not been readily adjustable. They could be taken out and reinstalled at a different angle, but this does not solve the problem of harvesting, when, perhaps, even in different parts of the same field the conditions may be different.
It is therefore another general object of the invention to provide for ready and rapid adjustment of the vine retarding tines, to adapt them to changing conditions, both as to their angle of inclination and as to their nearness to the walker bars of the separator.
The third problem to which this invention is directed, is to obtain better balanced operation of the crankshaft for the walking bars of the shaker unit. As stated earlier, the bars are pivotally mounted at their forward ends and are connected to the crankshaft at their rear ends. The connection to the crankshaft might seem to be a simple thing, but the fact is that there tends to be a drastic unbalance on the shaft itself which sets up lateral conditions that can result in vibrations and movements which tend to be destructive of the machine. The reasons for this unbalance will be explained in detail later.
It is therefore another general object of this invention to improve the balance of the crankshaft to provide for more efficient operation of the walking bars without setting up conditions destructive to the machine.
Other objects and advantages of the invention will appear from the following description of the machine, both in general and in a specific embodiment.